Besides the cories and loaches mentioned by Eddie, you won't be surprised either that loricariids(plecs) have mouths pointing downward.

If you want to keep cories, be sure to see that your gravel is not sharp as this also damages their delicate barbels. But this is not always the case. Even poor water quality will also cause the disintegration of barbels.
Fortunately, the barbels will grow back once water conditions are right.

I'm ready for the pressure.
The drama and the pleasure!If there is one thing I want to see here, it's HUMOR.I believe I can fly!
I believe I can touch the sky!
I think about it every night and day!I stand in awe of my body.